While a 727 with overdrive is the most likely candidate, there's a small chance of other transmissions having been swapped in over the years. Therefore, checking the tag is the only definitive way to know for sure.
If you find a 727 with an overdrive, the replacement will need to be a 727 with an electric overdrive. Simply finding a 727 isn't enough; the overdrive functionality is key. The year of the replacement transmission isn't as critical as matching the 727 designation and the presence of the electric overdrive.
Before attempting any transmission replacement:
* Confirm the transmission identification: This is paramount.
* Consider professional help: Transmission replacement is a complex job best left to experienced mechanics.
* Research compatibility: Even within 727 transmissions, there can be variations based on year and application. A reputable parts supplier (or mechanic) should be consulted to ensure compatibility.
Don't rely solely on the overdrive button; always verify the transmission type directly.